One suggestion that a friend gave me, was to use a thin line of Washable Elmers Glue and iron the two pieces together before sewing. It has been a great help to me; even though it does take a tad bit of extra time.

Yes on the starch - an enormous benefit.

And I second the recommendation of using glue.

A third tip for flying geese is this method (see link below). While you do still sew on the bias with this method, you do it before you cut it - not after. I've found that because I'm working with the whole square and sewing down the center, the fabric is a lot more stable.

http://members.shaw.ca/BeverlysQuiltingPage/ffg.htm

A much easier way to make flying geese is with one large sq. and two small squares, no trimming, no waste.

WWW.quilterscache.com/H/Howto make geese.html

The 3rd example is the one.

Another thing to try is something I saw on You Tube. I forget which instructor, but it was one of the major ones. She recommended taking a strip of iron on interfacing and attaching it on the bias where you will be sewing, this will stablize the fabric so it won't pucker when you sew.

This works well, as the glue stabilizes the sewing lines. I would use this method on pieces already cut, but I usually heavily starch fabric before cutting them. If you let the starch dry, you won't get as much starch on your irons sole plate, and the iron won't stick to the fabric either :) :) :)